Figure REF  shows two images from class 32 with red dots overlaid at tensor-state values overlapping with class 33 (top two rows). The bottom two rows illustrate two images from class 33 with red dot overlaid at tensor-state values characterizing all images in class 32. By comparing Figure REF  and Figure REF , one can observe that both classes (1) have common tensor-state values corresponding to the blue sky and saturated regions and (2) do not overlap in tensor-state values defining the foreground traffic signs (Parent and child and GIVE WAY) except from a small number of white pixels. Note that a few tensor-state values in the red rim of each traffic sign are common to each class according to Figure REF , but they are not common to both classes as they differ in the shades of red.
Following the classification of graph computation units as poly-semantic and mono-semantic neurons [1]}, [2]}, we can also conclude that layer1.2.conv2 is poly-semantic since it is constructing common and unique class characteristics in the two traffic sign classes and passing them to the downstream graph computation units.
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